Researchers tested whether adding oregano oil and special enzymes to chicken feed could improve egg production and chicken health. They studied 288 laying hens for 40 days, comparing regular feed to feed with natural supplements. The results showed that hens receiving the oregano oil and enzyme combination laid more eggs, produced stronger eggshells, and had better overall health markers. This research suggests that natural plant-based additives could be a healthier alternative to antibiotics in poultry farming, potentially improving both egg quality and chicken welfare.
The Quick Take
- What they studied: Whether adding oregano essential oil, lauric acid, and special digestive enzymes to chicken feed would improve egg production, egg quality, and overall chicken health
- Who participated: 288 Dagu breeder hens (a Chinese chicken breed known for quality eggs and meat) that were 38 weeks old at the start of the study
- Key finding: Hens that received both oregano oil and enzyme supplements together laid significantly more eggs (69.56% laying rate), produced stronger eggshells, and showed better health markers compared to hens eating regular feed
- What it means for you: If you eat eggs or chicken, this research suggests that using natural plant-based supplements instead of antibiotics could improve the quality and safety of poultry products. However, this study was done on one specific chicken breed, so results may differ with other types of chickens.
The Research Details
Scientists divided 288 healthy laying hens into four equal groups. One group ate regular chicken feed (the control group), while the other three groups ate the same feed but with added supplements: one group received oregano oil and lauric acid, another received enzyme supplements, and the final group received both supplements combined. All groups were fed and cared for identically except for the supplements. The study lasted 40 days, which is long enough to see changes in egg production and chicken health. The researchers carefully measured egg production, egg quality, how well the chickens digested their food, and various health markers in their blood and digestive systems.
This type of study design is called a controlled experiment because it compares groups receiving different treatments while keeping everything else the same. This helps researchers determine whether the supplements actually caused the improvements they observed, rather than other factors being responsible.
The researchers used standard statistical methods to analyze their data, meaning they used math to determine whether the differences between groups were large enough to be meaningful rather than just due to chance.
Understanding how natural supplements affect chicken health is important because the poultry industry is looking for alternatives to antibiotics. Overuse of antibiotics in farm animals has created bacteria that resist antibiotics, which is a serious public health concern. If natural plant-based supplements can improve chicken health and production without antibiotics, it could benefit both the chickens and people who eat their eggs and meat. This research specifically tested a Chinese chicken breed that produces high-quality eggs, so the findings could help improve food quality while supporting sustainable farming practices.
This study has several strengths: it used a reasonable number of chickens (288), had multiple treatment groups for comparison, and measured many different health and production outcomes. The researchers used proper statistical analysis to determine if results were meaningful. However, the study was relatively short (40 days), which is only about 1.3 months of a chicken’s productive life. The study focused on one specific chicken breed, so results might not apply equally to other breeds. The researchers don’t mention whether they were blinded to which group was which, which could potentially introduce bias. Additionally, the study was published in 2025, so it’s very recent research that may need confirmation from other studies.
What the Results Show
The most impressive result was that hens receiving both oregano oil and enzyme supplements together had a laying rate of 69.56%, meaning they produced eggs at a higher rate than the control group. These hens also needed less feed to produce each egg, which is more efficient. When hens received just the oregano oil supplement, they had 85% fewer broken or soft eggs compared to the control group, meaning the eggshells were significantly stronger.
The combination supplement also improved egg quality in measurable ways. Eggshells became about 7.66% stronger, and the Haugh unit (a measure of egg white quality) improved by 2.01%. These improvements matter because stronger eggshells mean fewer broken eggs during collection and transport, and better egg white quality means fresher-tasting eggs.
The supplements also boosted the chickens’ natural antioxidant systems, which are like the body’s defense against damage. Hens receiving the combination supplement showed improvements in multiple antioxidant markers: total antioxidant capacity increased 7.02%, an important protective enzyme called glutathione peroxidase increased 11.31%, and harmful molecules called malondialdehyde decreased 7.93%. These changes suggest the supplements helped protect the chickens’ cells from damage.
The supplements improved how well chickens digested their food. Hens receiving the combination supplement showed better absorption of important nutrients like protein (94.92% improvement), calcium (4.83% improvement), and phosphorus (2.53% improvement). The supplements also increased the activity of digestive enzymes—the combination supplement increased amylase activity by 9.23%, lipase by 12.86%, and trypsin by 9.99%. These enzymes are crucial for breaking down food and absorbing nutrients.
The supplements also improved the structure of the chickens’ intestines. The combination supplement improved the ratio of intestinal villi (finger-like structures that absorb nutrients) to crypts (the spaces between them) in two parts of the small intestine. A better ratio means the intestines can absorb more nutrients from food. These intestinal improvements help explain why the chickens had better overall health and production.
This research builds on previous studies showing that oregano oil and enzymes can benefit poultry health. Earlier research has demonstrated that oregano essential oil has antimicrobial and antioxidant properties that can improve gut health in chickens. Similarly, enzyme supplements have been shown to improve nutrient absorption in poultry. However, this study is notable because it tested the combination of these supplements together, which appears to produce better results than either supplement alone. This synergistic effect (where two things work better together than separately) is an important finding that suggests these supplements complement each other’s benefits.
This study has several important limitations to consider. First, it only lasted 40 days, which is relatively short for evaluating long-term effects on chicken health and production. Second, the study focused exclusively on one Chinese chicken breed (Dagu hens), so the results may not apply equally to other chicken breeds commonly raised in other countries. Third, the study doesn’t provide details about whether the researchers knew which group was receiving which treatment, which could potentially influence how they measured results. Fourth, the study doesn’t include information about the cost of these supplements compared to their benefits, which is important for farmers deciding whether to use them. Finally, while the study measured many health markers, it didn’t measure some other important factors like immune function or disease resistance, which would provide a more complete picture of the supplements’ effects.
The Bottom Line
Based on this research, there is moderate evidence that combining oregano oil and enzyme supplements may improve egg production and quality in laying hens. The evidence is strongest for the combination of both supplements together rather than either one alone. However, because this study was conducted on only one chicken breed over a relatively short period, farmers should consider conducting their own trials with their specific flocks before making large-scale changes. Consulting with a poultry nutritionist is recommended to determine appropriate dosages and implementation strategies for your specific situation.
This research is most relevant to commercial and small-scale poultry farmers looking to improve egg production and quality naturally. It’s also relevant to consumers interested in supporting sustainable farming practices that reduce antibiotic use. People with allergies to oregano or related plants should be aware of this ingredient. This research is less directly applicable to backyard chicken keepers with small flocks, though the principles might still apply. The findings are specific to laying hens and may not apply to meat chickens or other poultry species.
Based on the 40-day study period, improvements in egg production and quality appeared within 4-6 weeks of starting the supplements. However, the full benefits to chicken health (particularly the antioxidant improvements) may take several weeks to develop. Farmers should expect to see changes in egg production within 2-3 weeks, but should continue supplementation for at least 4-6 weeks to see the full range of benefits. Long-term effects beyond 40 days are unknown based on this study.
Want to Apply This Research?
- If managing a flock, track daily egg production numbers, percentage of broken or soft eggs, and feed consumption. Record these metrics weekly to monitor trends. For example: ‘Week 1: 85 eggs collected, 2 broken, 12 kg feed consumed’ to establish a baseline and track improvements over 4-6 weeks.
- For flock managers: Implement the supplement protocol by adding the oregano oil and enzyme mixture to feed at the recommended dosage, ensuring consistent daily feeding. For consumers: If you purchase eggs, look for producers using natural supplement programs rather than antibiotic-dependent practices, and track any perceived differences in egg quality or freshness.
- Establish a simple tracking system that records egg production, egg quality (broken eggs, shell strength), and feed efficiency weekly. Create a baseline before starting supplements, then compare measurements at 2, 4, and 6 weeks. Note any changes in flock health, behavior, or feed consumption. This allows you to determine whether the supplements are delivering the expected benefits for your specific situation.
This research describes results from a controlled study on one specific chicken breed over 40 days. Individual results may vary depending on chicken breed, farm conditions, feed quality, and management practices. This information is intended for educational purposes and should not replace professional veterinary or nutritional advice. Before implementing any new feed supplements or changes to your flock’s diet, consult with a veterinarian or poultry nutritionist. The study was conducted in a research setting and may not reflect real-world farm conditions. Always follow product label instructions and local regulations regarding feed additives. If you have concerns about your flock’s health or production, contact a qualified poultry veterinarian.